As mentioned, your temp are too high. A larger exhaust fan is recommended. You can connect the fan to dimmer switch to modulate it and find the perfect volume. Two large fans running on low is a LOT quieter than one tiny fan running wild.

Mylar on the walls is actually not very good. There are a lot of stories on this, but basically Mylar only lights up the areas that are in direct reflection of the light.

Example: Cut a piece of Mylar 8½x11. Put that piece of Mylar and a sheet of plain white copy paper next to each other directly under a lamp. Turn off all the other light in the room and move the pieces around. Look at the rest of the unlit room and whichever material lights up the room the best, is the one you should use. Mylar will cast a reflection straight up. The white paper will act like another lamp and the whole room is brighter. Therefore, your walls should be covered in white plastic (see panda film) or painted Flat White.